“Mutated H5N1 Bird Flu Virus Found in Cats: What You Need to Know”

A genetic mutation of the H5N1 bird flu virus has been discovered in two cats, raising concerns among scientists about the potential risks posed by the virus. The mutation, known as PB2 E627K, is associated with increased infectiousness and disease severity in mammals.

Seema Lakdawala, a microbiologist at Emory University, emphasized the significance of this finding, stating that it is a clear indication of how the virus is evolving in nature and should be a cause for concern for everyone. Henry Niman, founder of Recombinomics Inc., reviewed the sequence data and confirmed the presence of the mutation in the cats.

The cats were infected with the D1.1 strain of H5N1, which is widespread in wild birds and has also been detected in cattle herds in Nevada and Arizona. Niman believes that the cats, located in New Jersey, were infected last month based on the genetic sequencing data.

Since the beginning of 2025, the U.S. Department of Agriculture has reported 51 cases of H5N1-infected cats in 13 states, including California, Montana, Colorado, Oregon, Washington, and New Jersey. The New Jersey Department of Public Health confirmed that all infected cats lived on the same property, with one being feral and another being an indoor/outdoor cat.

The genetic sequences of the virus from the infected cats have been added to the GISAID database for public access. Richard Webby, an infectious disease expert, noted that while the mutation is not alarming on its own, it could become concerning if it spreads more widely.

As of now, there have been no reports of infected humans in New Jersey, and individuals who interacted with the infected cats have shown no symptoms. The infected cats had no known exposure to infected poultry or livestock, but did roam outdoors, potentially exposing them to wild birds or other animals.

Since the outbreak began last March, 70 people in the U.S. have been infected with H5N1, resulting in one death. The discovery of the mutation in the cats underscores the ongoing threat posed by the virus and the need for continued vigilance in monitoring and controlling its spread.